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-rw-r--r--lld/include/lld/ReaderWriter/ELFTargetInfo.h20
-rw-r--r--lld/lib/Driver/GnuLdDriver.cpp7
-rw-r--r--lld/lib/Driver/LDOptions.td8
-rw-r--r--lld/lib/ReaderWriter/ELF/DynamicLibraryWriter.h6
-rw-r--r--lld/lib/ReaderWriter/ELF/ExecutableWriter.h20
-rw-r--r--lld/lib/ReaderWriter/ELF/OutputELFWriter.h30
-rw-r--r--lld/test/elf/X86_64/Inputs/libfn.abin0 -> 1364 bytes
-rw-r--r--lld/test/elf/X86_64/undef.test19
8 files changed, 92 insertions, 18 deletions
diff --git a/lld/include/lld/ReaderWriter/ELFTargetInfo.h b/lld/include/lld/ReaderWriter/ELFTargetInfo.h
index af8e00df118..b8f7da89fe9 100644
--- a/lld/include/lld/ReaderWriter/ELFTargetInfo.h
+++ b/lld/include/lld/ReaderWriter/ELFTargetInfo.h
@@ -12,6 +12,7 @@
#include "lld/Core/PassManager.h"
#include "lld/Core/Pass.h"
+#include "lld/Core/range.h"
#include "lld/Core/TargetInfo.h"
#include "lld/ReaderWriter/Reader.h"
#include "lld/ReaderWriter/Writer.h"
@@ -154,6 +155,22 @@ public:
/// Searches directories then calls appendInputFile()
bool appendLibrary(StringRef libName);
+ /// adds undefined symbols that are specified in the command line
+ void addUndefinedSymbol(StringRef symbolName) {
+ _undefinedSymbols.push_back(symbolName);
+ }
+
+ /// Iterators for symbols that appear on the command line
+ typedef std::vector<StringRef> StringRefVector;
+ typedef StringRefVector::iterator StringRefVectorIter;
+ typedef StringRefVector::const_iterator StringRefVectorConstIter;
+
+ /// Return the list of undefined symbols that are specified in the
+ /// linker command line, using the -u option.
+ range<const StringRef *> undefinedSymbols() const {
+ return _undefinedSymbols;
+ }
+
private:
ELFTargetInfo() LLVM_DELETED_FUNCTION;
protected:
@@ -174,12 +191,13 @@ protected:
bool _dynamicLinkerArg;
bool _noAllowDynamicLibraries;
OutputMagic _outputMagic;
- std::vector<StringRef> _inputSearchPaths;
+ StringRefVector _inputSearchPaths;
llvm::BumpPtrAllocator _extraStrings;
std::unique_ptr<Reader> _elfReader;
std::unique_ptr<Writer> _writer;
std::unique_ptr<Reader> _linkerScriptReader;
StringRef _dynamicLinkerPath;
+ StringRefVector _undefinedSymbols;
};
} // end namespace lld
diff --git a/lld/lib/Driver/GnuLdDriver.cpp b/lld/lib/Driver/GnuLdDriver.cpp
index 57ee99b0fc2..0f8df29fc60 100644
--- a/lld/lib/Driver/GnuLdDriver.cpp
+++ b/lld/lib/Driver/GnuLdDriver.cpp
@@ -217,6 +217,13 @@ GnuLdDriver::parse(int argc, const char *argv[], raw_ostream &diagnostics) {
if (!options->allowLinkWithDynamicLibraries())
options->setIsStaticExecutable(true);
+ // Handle -u, --undefined option
+ for (llvm::opt::arg_iterator it = parsedArgs->filtered_begin(OPT_u),
+ ie = parsedArgs->filtered_end();
+ it != ie; ++it) {
+ options->addUndefinedSymbol((*it)->getValue());
+ }
+
// Handle -Lxxx
for (llvm::opt::arg_iterator it = parsedArgs->filtered_begin(OPT_L),
ie = parsedArgs->filtered_end();
diff --git a/lld/lib/Driver/LDOptions.td b/lld/lib/Driver/LDOptions.td
index ef605aed55f..e941d547c9b 100644
--- a/lld/lib/Driver/LDOptions.td
+++ b/lld/lib/Driver/LDOptions.td
@@ -72,6 +72,14 @@ def omagic_alias : Flag<["-"], "N">, Alias<omagic>;
def no_omagic : Flag<["--"], "no-omagic">,
HelpText<"This option negates most of the effects of the -N option. Disable linking with shared libraries">;
+// TODO: remove the options with the = sign, once the change in the OptionParser
+// is done to recognize the allowed suffixes for an argument.
+def u : Separate<["-"], "u">,
+ HelpText<"Force symbol to be entered in the output file as an undefined symbol">;
+def undefined : Separate<["--"], "undefined">, Alias<u>;
+def u_equal : Joined<["-"], "u=">, Alias<u>;
+def undefined_equal : Joined<["--"], "undefined=">, Alias<u>;
+
// extensions
def emit_yaml : Flag<["-"], "emit-yaml">,
HelpText<"Write YAML instead of ELF">;
diff --git a/lld/lib/ReaderWriter/ELF/DynamicLibraryWriter.h b/lld/lib/ReaderWriter/ELF/DynamicLibraryWriter.h
index ef084d4c735..4eda0adc3c4 100644
--- a/lld/lib/ReaderWriter/ELF/DynamicLibraryWriter.h
+++ b/lld/lib/ReaderWriter/ELF/DynamicLibraryWriter.h
@@ -31,7 +31,6 @@ public:
private:
void buildDynamicSymbolTable(const File &file);
void addDefaultAtoms();
- void addFiles(InputFiles&);
void finalizeDefaultAtomValues();
llvm::BumpPtrAllocator _alloc;
@@ -63,11 +62,6 @@ void DynamicLibraryWriter<ELFT>::buildDynamicSymbolTable(const File &file) {
template<class ELFT>
void DynamicLibraryWriter<ELFT>::addDefaultAtoms() { }
-template <class ELFT>
-void DynamicLibraryWriter<ELFT>::addFiles(InputFiles &inputFiles) {
- this->_targetHandler.addFiles(inputFiles);
-}
-
template<class ELFT>
void DynamicLibraryWriter<ELFT>::finalizeDefaultAtomValues() {
this->_targetHandler.finalizeSymbolValues();
diff --git a/lld/lib/ReaderWriter/ELF/ExecutableWriter.h b/lld/lib/ReaderWriter/ELF/ExecutableWriter.h
index 735627c34dc..de688c6280e 100644
--- a/lld/lib/ReaderWriter/ELF/ExecutableWriter.h
+++ b/lld/lib/ReaderWriter/ELF/ExecutableWriter.h
@@ -64,10 +64,13 @@ void ExecutableWriter<ELFT>::addDefaultAtoms() {
/// \brief Hook in lld to add CRuntime file
template <class ELFT>
void ExecutableWriter<ELFT>::addFiles(InputFiles &inputFiles) {
+ // Add the default atoms as defined by executables
addDefaultAtoms();
+ // Add the runtime file
inputFiles.prependFile(_runtimeFile);
- // Give a chance for the target to add atoms
- this->_targetHandler.addFiles(inputFiles);
+ // Add the Linker internal file for symbols that are defined by
+ // command line options
+ OutputELFWriter<ELFT>::addFiles(inputFiles);
}
template <class ELFT> void ExecutableWriter<ELFT>::createDefaultSections() {
@@ -120,11 +123,14 @@ template <class ELFT> void ExecutableWriter<ELFT>::finalizeDefaultAtomValues() {
auto bssSection = this->_layout->findOutputSection(".bss");
- (*bssStartAtomIter)->_virtualAddr = bssSection->virtualAddr();
- (*bssEndAtomIter)->_virtualAddr =
- bssSection->virtualAddr() + bssSection->memSize();
- (*underScoreEndAtomIter)->_virtualAddr = (*bssEndAtomIter)->_virtualAddr;
- (*endAtomIter)->_virtualAddr = (*bssEndAtomIter)->_virtualAddr;
+ // If we dont find a bss section, then dont set these values
+ if (bssSection) {
+ (*bssStartAtomIter)->_virtualAddr = bssSection->virtualAddr();
+ (*bssEndAtomIter)->_virtualAddr =
+ bssSection->virtualAddr() + bssSection->memSize();
+ (*underScoreEndAtomIter)->_virtualAddr = (*bssEndAtomIter)->_virtualAddr;
+ (*endAtomIter)->_virtualAddr = (*bssEndAtomIter)->_virtualAddr;
+ }
// Give a chance for the target to finalize its atom values
this->_targetHandler.finalizeSymbolValues();
diff --git a/lld/lib/ReaderWriter/ELF/OutputELFWriter.h b/lld/lib/ReaderWriter/ELF/OutputELFWriter.h
index 32bc12c9e7b..90788f4274f 100644
--- a/lld/lib/ReaderWriter/ELF/OutputELFWriter.h
+++ b/lld/lib/ReaderWriter/ELF/OutputELFWriter.h
@@ -28,6 +28,15 @@ using namespace llvm::object;
template<class ELFT>
class OutputELFWriter;
+/// \brief This acts as a internal file that the linker uses to add
+/// undefined symbols that are defined by using the linker options such
+/// as -u, or --defsym option.
+template <class ELFT> class LinkerInternalFile : public CRuntimeFile<ELFT> {
+public:
+ LinkerInternalFile(const ELFTargetInfo &ti)
+ : CRuntimeFile<ELFT>(ti, "Linker Internal File") {};
+};
+
//===----------------------------------------------------------------------===//
// OutputELFWriter Class
//===----------------------------------------------------------------------===//
@@ -78,7 +87,7 @@ protected:
virtual void addDefaultAtoms() = 0;
// Add any runtime files and their atoms to the output
- virtual void addFiles(InputFiles&) = 0;
+ virtual void addFiles(InputFiles &);
// Finalize the default atom values
virtual void finalizeDefaultAtomValues() = 0;
@@ -114,6 +123,7 @@ protected:
LLD_UNIQUE_BUMP_PTR(HashSection<ELFT>) _hashTable;
llvm::StringSet<> _soNeeded;
/// @}
+ LinkerInternalFile<ELFT> _linkerInternalFile;
};
//===----------------------------------------------------------------------===//
@@ -121,7 +131,8 @@ protected:
//===----------------------------------------------------------------------===//
template <class ELFT>
OutputELFWriter<ELFT>::OutputELFWriter(const ELFTargetInfo &ti)
- : _targetInfo(ti), _targetHandler(ti.getTargetHandler<ELFT>()) {
+ : _targetInfo(ti), _targetHandler(ti.getTargetHandler<ELFT>()),
+ _linkerInternalFile(ti) {
_layout = &_targetHandler.targetLayout();
}
@@ -223,8 +234,19 @@ void OutputELFWriter<ELFT>::assignSectionsWithNoSegments() {
_shdrtab->updateSection(section);
}
-template<class ELFT>
-void OutputELFWriter<ELFT>::createDefaultSections() {
+template <class ELFT>
+void OutputELFWriter<ELFT>::addFiles(InputFiles &inputFiles) {
+ // Add all input Files that are defined by the target
+ _targetHandler.addFiles(inputFiles);
+ // Add all symbols that are specified by the -u option
+ // as part of the command line argument to lld
+ for (auto ai : _targetInfo.undefinedSymbols())
+ _linkerInternalFile.addUndefinedAtom(ai);
+ // Make the linker internal file to be the first file
+ inputFiles.prependFile(_linkerInternalFile);
+}
+
+template <class ELFT> void OutputELFWriter<ELFT>::createDefaultSections() {
_Header.reset(new (_alloc) Header<ELFT>(_targetInfo));
_programHeader.reset(new (_alloc) ProgramHeader<ELFT>(_targetInfo));
_layout->setHeader(_Header.get());
diff --git a/lld/test/elf/X86_64/Inputs/libfn.a b/lld/test/elf/X86_64/Inputs/libfn.a
new file mode 100644
index 00000000000..380844b0838
--- /dev/null
+++ b/lld/test/elf/X86_64/Inputs/libfn.a
Binary files differ
diff --git a/lld/test/elf/X86_64/undef.test b/lld/test/elf/X86_64/undef.test
new file mode 100644
index 00000000000..b75300d89b0
--- /dev/null
+++ b/lld/test/elf/X86_64/undef.test
@@ -0,0 +1,19 @@
+# This tests the functionality that an undefined symbol thats defined in the
+# commmand line pulls in the required object file from the archive library
+# which is usually the usecase for it
+RUN: lld -flavor gnu -target x86_64 -u fn %p/Inputs/libfn.a -o %t --noinhibit-exec
+RUN: llvm-readobj -symbols %t | FileCheck -check-prefix=SYMFROMARCHIVE %s
+RUN: lld -flavor gnu -target x86_64 %p/Inputs/libfn.a -o %t --noinhibit-exec
+RUN: llvm-readobj -symbols %t | FileCheck %s
+
+SYMFROMARCHIVE: Symbol {
+SYMFROMARCHIVE: Name: fn (16)
+SYMFROMARCHIVE: Value: 0x4001A4
+SYMFROMARCHIVE: Size: 11
+SYMFROMARCHIVE: Binding: Global (0x1)
+SYMFROMARCHIVE: Type: Function (0x2)
+SYMFROMARCHIVE: Other: 0
+SYMFROMARCHIVE: Section: .text (0x5)
+SYMFROMARCHIVE: }
+
+CHECK-NOT: Name: fn
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